1. Field of the Invention
The invention relates to secure processors and to secure software execution thereon, such as for example to secure processors capable of secure execution of application software.
2. Related Art
In known computing systems, the availability of processing capability, such as provided by microprocessors and other processing devices, is no longer a significant limit when considering the value of the computing system. Availability of application software and multimedia content, or more precisely, authorization to use that application software and multimedia content, for execution by those processors (and for presentation by those processors) has become a substantial limit. One effect of this is that a substantial value to many computing systems is the application software and multimedia content that executes on the device or platform. Both application software and multimedia content have become more easily distributed, such as for example using a communication network or by distribution using inexpensive CD-ROM media, with the effect that protecting against unauthorized copying and distribution (sometimes called “software piracy”) has become an economically important concern. Accordingly, one problem in the known art is to assure that such application software and multimedia content, being valuable, are only used on processors when the right to do so has been authorized, such as for example when that right has been properly paid for, or the integrity of the content verified with respect to information from a trusted content publishing entity.
Another problem in the known art is that, while it is desired to provide application software and multimedia content with the property that such application software and multimedia content cannot be used on processors without authorization or alteration, it is not desirable to redesign or re-author the application software or multimedia content to provide this property. There is a sufficient set of application software and multimedia content available, and the value of that application software and multimedia content is sufficiently large, that the approach of altering that application software or that multimedia content would likely be expensive, unreliable, and unwieldy.
Accordingly, it would be advantageous to restrict application software and multimedia content to those processors for which that application software and multimedia content is authorized, without having to substantially alter the original application software or multimedia content.